Stop clock reset mechanism



Jan. 20, 1959 Filed July 8, 1954 J. J. AMBROZAITIS STOP CLOCK RESETMECHANISM 3 Sheets-Sheet 1 I ai s I )4 40 58 fici. 1.

INVENTOR.

Js/m d Ambroza/f/s AGEN T.

J. J. AMBROZAITIS STOP CLOCK RESET MECHANISM Jan. 20, 1959 3Sheets-Sheet 3 Filed July 8, 1954 WA\\\\.M\\\\-\\\\\\-\\X\\\\\\\\\\\\ WmH U H 1 .1 s H 1 a V\ m 4 B M s H A i a m m m u M flop H w H w H H H r Hw\\ \7 H H M H n w MN 1 IN V EN TOR. /o/m fllmra 24/ f/s AGINI:

Un S ew Pe m? r 2,869,639 ISTO'P CLOCK RESET MECHANISM John J.Ambrozaitis, Waterbury, Conn., assignor, by

mesne assignments, to Consolidated Electronics Industries Crp., Jackson,Mich., a corporation of Delaware Application July 8, 1954, Serial No.442,061

4 Claims. (Cl. 161-15) hand and a second hand, all of which rotate in atiming operation but which are rapidly reset for subsequent tim ingoperations.

A further object of the present invention is to provide a reset clockwhich is driven by a reversible motor through a gear train arranged soas to drive each of the i stop clock pointers in a timing sequence whenthe motor rotates in one direction and upon reversal of the direction ofrotation of the motor to reset the pointers rapidly to the zero positionof the stop clock. v

A further object of the present invention isto provide a reset clockwhich has the slippage means as well as the reset arms and locking teetharranged on one shaft. 1 His a further object of the present inventionto substantially eliminate the inaccuracies caused by the change in loadon the governed motorthereby affecting its governing action. This is ofgreat importance when the stop clock mechanism changes from idling totiming operation. Therefore, in order to substantially eliminate theaforesaid inaccuracies a load equal to the timing load is incorporatedin the clutch. This equalizes the motor load for both the idling andtiming periods leaving the governor virtually unaffected during theoperation of the present stop clock mechanism.

The above and other features, objects and advantages of the presentinvention will be fully understood from the following descriptionconsidered in connection with the accompanying illustrative drawings.

Fig. 1 is a side elevational view of the reset mechanism embodying thepresent invention being partly in section,

Fig. 2 is a top plan fragmentary view illustrating a reset arm and alocking tooth employed in the present invention,

Fig. 3 is a fragmentary front elevation view of the elements shown inFig. 2,

Fig. 4 is a fragmentary front elevation view of a friction fingerembracing the lower shaft of the present reset mechanism,

' Fig. 5 is a side elevational view of a modification of the resetmechanism embodying the present invention, being partly in section,

Fig. 6 is a diagramamtic view of the reset finger employed in themodification of the present invention shown in Fig. 5,

Fig. 7 is a perspective view of the friction element utilized in themodification of the present invention shown in Fig. 5.

Patented Jan. 20, 1959 ice Referring to the drawings and moreparticularly to Fig. 1 the stop clock embodying the present inventioncomprises a frame 8 and a gear train assembly therein preferably drivenby a reversible motor 10, provision being made in the motor drive forsome lost motion during reset operation in order to prevent the stallingof the motor on reset and to prevent damage to the gears. The motor 10through suitable clutching mechanism drives a shaft 12 on which ismounted a series of gears, pinions and other elements which willhereinafter be disclosed in detail.

The clutching mechanism or driving connection which as indicated is ofthe slip type, that is it provides for some lost motion during resetoperation, is indicated in general by the reference numeral 22 and maybe the same as that specifically described below in connection withFigure 5.

On the extreme free end of the shaft 12 and in front of a dial face 14are three pointers 16, 18 and 20 respectively. Pointer 16 is what I termthe hour hand in that it rotates once each hour, while pointers 18 and20 are what I term the minute and second hands respectively in that theyrotate once each minute and once each second respectively. A shaft 13 ispositioned parallel to shaft 12 and mounted on both ends in frame 8. Thepinion 28 fixedly mounted on shaft 12 engages gear 30 which is freelymounted on shaft 13 to rotate the latter in a counter-clockwisedirection. A pinion 32 is loosely mounted on shaft 13 and has anintegral extension 34 provided with a smooth circumference. Gear 36fixediy mounted on hollow shaft 12a (freely mounted on shaft 12) isdriven by pinion 32 and is operative to drive the minute hand 18 whichis fixedly secured on the end of shaft 12a. Likewise, the hour hand 16which is fixedly secured to the end of a hollow shaft 12!) is driven bythe gear 42 also fixedly mounted on shaft 12b through pinion 40 which isloosely mounted on the lower shaft 13 and counter-clockwise rotatinggear 38 loosely mounted on shaft 13, which in turn is driven by pinion3'7 fixedly mounted on shaft 12a. Pinion 40 is provided with anextension 41 similar in construction to extension 34 hereinbeforediscussed.

In operation, pointer shafts 12, 12a and 12b rotate together with thegears thereon in a clockwise direction. The gear ratio arrangementscause the pointers to rotate in a certain sequence relative to eachother to thereby give directreadings on the dial face in fractions of anhour, or minutes ointer 16), fractions of a minute, or seconds (pointer18) and fractions of a second (pointer 20).

Shafts 12, 12a and 12b have preferably three similar reset arms 44, 46and 48 respectively mounted thereon which take the form of curved,flexible springs (see Fig. 3 for shape of arms). On gears 36 and 42 arepositioned wedge-shaped locking teeth 50 and 52. It is to be noted thatit is within the scope of the invention to alternately make the teethintegral, or separate from the gear but affixed thereto. An additionallocking tooth 54 similar in shape to teeth 50 and 52, is secured to theframe 8 (see Fig. 2 for shape of teeth).

When the shafts 12, 12a and 12b rotate in the clockwise direction andthe stop clock is timing, the reset arms all ride over the upwardlysloping sides of the wedgeshaped locking teeth. However, when the motor10 is reversed, the reset arms rotate counterclockwise until the armsabut against a side of each of said locking teeth which is perpendicularto the plane of gears 36 and A pair of friction fingers 56 and 58 arefixed to the gears 30 and 38 respectively. The aforesaid frictionfingets may be bifurcated so that the arms thereof may surround aportion of each of the extensions 34 and 41 of pinions 32 and 40,respectively and grasp the same.

Thus, on direct drive both the friction fingers 56 and 58 grasp theextensions 34 and 41 in order to transmit the direct driving power ofthe motor ft to the pinions 32 and 49 from gears 36 and 38. However whenthe direction of rotation of the motor is reversed the friction fingers56 and 58 slip on extensions 34 and 61 thus permitting the pinions 32and 40 to move relative to gears 30 and 3t, and all the pointers torevolve back to their starting positions substantially at a rate of l R.P. S. (the rate of shaft 12). In this regard, it should be noted that inthe normal timing operation the pointer 16 revolves around the dial face14 at the rate of 1 R. P. 1-1., the pointer 18 at the rate of 1 R. P.M., and the pointer 20 at the rate of l R. P. S. Yet in the resettingoperation all the pointers are reset to their starting position in nomore than three seconds by reason of the fact that shafts 12a and 12bare driven directly from shaft 12 through reset arms .4 and 46. Thefixed locking tooth 54 on the frame 3 determines the commencement pointof the timing sequence for pointer 16 and the other pointers 18 and 21respectively are brought into alignment with the pointer 16 and insuperposed relation thereto, the location of stoppage of the gears andpinions of the device being determined by the reset or commencementposition of gear 42. When the pointers have all reached their resetpositions the gears of the device will not be damaged and the motor willnot be stalled since there is provision made, as indicated, in the drivefor lost motion or slip which will overcome the aforesaid prospectivedangers and give the operator time to either put the motor in directdrive or stop the same.

Referring now to Fig. 5 there is shown an alternative embodiment of theinvention wherein shaft 60 is rotated by a reversible motor 62 and ashaft 64 is positioned parallel to and below shaft 60. The drivingconnection between the motor 62 and shaft 60 is, as is that in theprevious embodiment, of the slip clutch variety and contains provisionfor continuing loading of the motor. Upon the output shaft 91]) of motor62 is fixed a collar member $1 containing a circumferential groove 92,the latter being adapted to be continually engaged by a friction clip 93secured to a pin 94 on a fly wheel 95. Fly wheel 95 is fixedly securedto what may be termed the input end of shaft 69 and is provided with abearing 96 in which the free end of output shaft 9 of motor 62 may berotatably received. The normal friction developed by the friction clip93 and collar member 91 is sufficient to provide a driving connectionbetween the collar and the fiy wheel 95 and hence between shaft 90 andshaft 60.

Shafts 6t) and 64 are similar in construction to shafts 12 and is orilgLifC l and the operation of the pointers through the gears andpinions mounted on shafts 6d and 6 is the same as described inconnection with the construction shown in Fig. 1 except that a frictionelement 66 is fixedly mounted on the hub 76 of a hollow shaft 75 whichis in turn mounted loosely on shaft 69. Element 66 is bifurcated at oneend 68 and is provided with an upwardly-sloping portion 67. Fixedlymounted on shaft 6!) is a curved spring-like reset finger member 70which in clockwise rotation of the shaft 69 rides over theupwardly-sloping portion 67 of bifurcated end 6? of element 66. Howeverupon counter-clockwise rotation of the shaft the member 76 engages theunderside of upwardly-sloping portion 67 of element 66. Thus, theelement 66 and the member itl take the place of the reset arm and thelocking tooth, e. g. 46 and 52, as shown in Fig. 1. it should be notedthat the member 70 is rigidly connected to a ointer 72 through shaft 6%while element 66 is rigidly connected to a pointer 74 through hollowshaft 75. Thus, on reset of the clock mechanism, the member '78 inreversing carries along the pointer 72 While the e it 25 carries thepointer '74 along with it thereby both pointers '72 and 74 to theirstarting or zero position which is established by a tooth 38 on theframe and reset arm 84 fixedly secured on shaft 75. Pointer 72 is thefast pointer mounted directly on shaft while pointer 74 is the slowpointer mounted directly on hub 76 of shaft 75. A gear A is looselymounted on hub 76 of the slow pointer assembly. Freely mounted on shaft64 is a pinion 65 which is driven by gear tit), fixed thereto, from apinion 73 fixed to shaft 60. Pinion 65 drives the slow pointer assemblybecause of the friction applied at B (a friction pad frictionallyconnecting gear A and hub 76) and C (area of frictional engagement offriction element 66 and gear A) in the clockwise rotation of the entireassembly. During reset operation, however, when shaft 60 is driven inthe reverse direction, the assembly slips at B and C to permit a rapidreset of the aforesaid pointers to the zero starting position. Fig. 6shows the reset finger member and the upwardly sloping portion 67 ofbifurcated end 68 of friction element 66 in one position in theresetting se quence according to the present invention. It is to benoted that in the timing sequence the member 70 climbs and passes overthe upwardly-sloping portion 67 while in the resetting sequence (Fig. 6)the member 70 is observed engaging the underside of upwardly-slopingportion 67 to carry element 66 together with pointer 74 at the speedrate of the fast pointer 72 in a counter-clockwise direction until thezero reset position determined by tooth 83 is attained.

While I have shown and described the preferred embodiment of myinvention, it will be understood that the latter may be embodiedotherwise than as herein specifically illustrated or described and thatin the illustrated embodiment certain changes in the details ofconstruction and in the arrangement of parts may be made withoutdeparting from the underlying idea or principle of the invention withinthe scope of the appended claims.

What I claim is:

1. A reset mechanism for a stop clock comprising a reversible motor, twopointer shafts, means operatively connecting one pointer shaft to saidmotor, one of said pointer shafts being hollow and having the otherpointer shaft positioned concentrically therein, a gear assembly mountedon each of said pointer shafts, a dial face plate having an aperturetherein, one end of each of said pointer shafts projecting through saidaperture, a pointer mounted on said one end of each of said pointershafts and in front of said dial face plate, a secondary shaft spacedfrom said pointer shafts, a pinion and gear assembly mounted on saidsecondary shaft and operatively connected to said gear assemblies ofboth of said pointer shafts, at least one locking element for each ofsaid pointer shafts, a reset arm operatively attached to each of saidpointer shafts and so constructed and arranged that when said pointershafts rotate in one direction said reset arms pass over said lockingelements and when said pointer shafts rotate in an opposite directionsaid reset arms engage said locking elements to rotate said pointerstogether and return them only so far as their starting positions wherethey are in effect in locked condition, against further movement, by thelocking elements, said operative connection between said pinion and gearassembly on said secondary shaft and the gear assembly on one of saidpointer shafts including a friction member mounted to engage the face ofa gear of said pinion and gear assembly and said last mentioned gearassembly, and means to provide lost motion between said motor and thepointer shaft to which the motor is operatively connected when saidmotor is operating against said locked condition of the pointers.

2. A reset mechanism for a stop clock comprising a reversible motor, apointer shaft operatively connected to said motor, a first pinion andgear assembly mounted on said pointer shaft, a dial face plate having anaperture therein, one end of said pointer shaft projecting through saidaperture, at least two pointers mounted on said one end and in front ofsaid dial face plate, a secondary shaft spaced from said pointer shaft,a second pinion and gear assembly mounted on said secondary shaft andoperatively connected to said first pinion and gear assembly, a lockingtooth on the gear of said first pinion and gear assembly, acorresponding reset arm for said locking tooth secured to said pointershaft, said reset arm and said locking tooth being so constructed andarranged that when said pointer shaft rotates in one direction saidreset arm passes over said locking tooth and when said pointer shaftrotates in an opposite direction said reset arm engages said lockingtooth to rotate the pointers counterclockwise and back to their startingposition together, and a friction device carried by and interconnectingthe gear and pinion of said second pinion and gear assembly on saidsecondary shaft, said friction device being so constructed and arrangedthat in one direction of rotation of said motor said friction devicedrivingly interconnects the pinion and gear mounted on said secondaryshaft positively and in the other direction of rotation of said motorpermits said last-mentioned pinion to slip relative to saidlast-mentioned gear to permit a rapid reset of said pointers.

3. A reset mechanism according to claim 2 in which said friction devicecomprises a pair of friction fingers mounted on the gear supported onthe secondary shaft and an integral extension of the pinion mounted onsaid secondary shaft, the friction fingers frictionaliy engaging saidintegral extension.

4. A reset mechanism according to claim 1 in which the pinion and gearon said secondary shaft are fixed with respect to each other and one ofsaid gears on a pointer shaft is frictionally mounted thereon to providein a reset operation for relative movement between it and its pointershaft.

References Cited in the file of this patent UNITED STATES PATENTS1,563,770 Marden Dec. 1, 1925 2,109,352 Hazard Feb. 22, 1938 2,730,913Friedman Jan. 17, 1956

